Title :
Structure and magnetic properties of RCo9Si2 systems
Author :
Pourarian, F. ; Malik, S.K. ; Boltich, E.B. ; Sankar, S.G. ; Wallace, W.E.
Author_Institution :
Mellon Inst., Carnegie-Mellon Univ., Pittsburgh, PA, USA
fDate :
9/1/1989 12:00:00 AM
Abstract :
RCo9Si2 alloys (R=Sm, Gd, Tb, and Er) were synthesized and examined by X-ray diffraction and high-field (90 kOe) magnetometry in the temperature range 4.2 to 700 K. X-ray powder diffraction analyses indicated that the major phase crystallizes in the tetragonal BaCd11-type structure. The presence of a small amount of extraneous phase was also detected. The magnetic ordering temperatures were observed to vary between 415 and 483 K in order Er, Tb, Gd, and Sm. This behavior is found to follow the de Gennes function and can therefore be ascribed to the strength of the rare-earth-cobalt exchange interaction. The average Co moment in RCo9Si2 was determined to be nearly 0.9 μmB at 4.2 K. All compounds studied showed an increase in magnetization with field, beyond technical saturation in fields up to 90 kOe. The M versus T on SmCo9Si2 indicates a spin reorientation transition at about 60 K. This can be attributed to the effect of the competing anisotropies of the Sm and Co sublattices
Keywords :
cobalt alloys; crystal atomic structure of alloys; erbium alloys; ferromagnetic properties of substances; gadolinium alloys; samarium alloys; silicon alloys; terbium alloys; 4.2 to 700 K; Co moment; ErCo9Si2; GdCo9Si2; M/T curve; SmCo9Si2; TbCo9Si2; X-ray diffraction; X-ray powder diffraction analyses; competing anisotropies; de Gennes function; extraneous phase; high field magnetometry; magnetic ordering temperatures; magnetic properties; magnetization; rare earth Co exchange interaction; spin reorientation transition; temperature range; tetragonal BaCd11-type structure; Erbium; Magnetic analysis; Magnetic anisotropy; Magnetic properties; Perpendicular magnetic anisotropy; Powders; Saturation magnetization; Silicon alloys; Temperature distribution; X-ray diffraction;
Journal_Title :
Magnetics, IEEE Transactions on
